1. Python 3.6.4rc1 is the first release candidate for Python 3.6.4, the nextmaintenance release of Python 3.6. While 3.6.4rc1 is a preview release and,thus, not intended for production environments, we encourage you to exploreit and provide feedback via the Python bug tracker (https://bugs.python.org).3.6.4 is planned for final release on 2017-12-18 with the next maintenancerelease expected to follow in about 3 months. You can find Python 3.6.4rc1and more information here:https://www.python.org/downloads/release/python-364rc1/

2. Python 3.7.0a3 is the third of four planned alpha releases of Python 3.7,the next feature release of Python. During the alpha phase, Python 3.7remains under heavy development: additional features will be addedand existing features may be modified or deleted. Please keep in mindthat this is a preview release and its use is not recommended forproduction environments. The next preview release, 3.7.0a4, is plannedfor 2018-01-08. You can find Python 3.7.0a3 and more information here:https://www.python.org/downloads/release/python-370a3/